Floating furosemide gel beads: in vitro and in vivo evaluation

Buoyant beads enclosing furosemide were prepared by cross-linking chitosan with dioctyl sodium sulphosuccinate (DOSS) and characterized according to: entrapment efficiency, in vitro release, in vitro and in vivo buoyancy. The effect of various factors (DOSS and chitosan concentrations, drug: polymer ratio and loading technique) on bead properties were assessed. Interaction between chitosan and DOSS was evaluated by DSC and FTIR. SEM demonstrated that the dried beads were spherical in shape with an inward cavity enclosing furosemide in the range of 1.8-62.25 %. Most beads floated over SGF for 12 h. Beads retarded the release of furosemide compared to pure drug powder and Lasix tablets. The t50 % ranged from 1.79-4.1 h and release followed zero or diffusion kinetics. Beads remained buoyant in the stomach of dogs for 6 h. Beads were stable at 40 °C and 75 % RH for 3 months. Results showed that chitosan beads proved to be effective carrier for furosemide, maximizing its therapeutic effect at the site of absorption in a controlled release pattern.